The present invention pertain to an oil pressure control apparatus for an automatic transmission mounted on a vehicle, for example, and relates in particular to an oil pressure control apparatus for an automatic transmission in which an oil pressure servo that engages and disengages one friction engagement element includes two hydraulic oil chambers so that the friction engagement element is engaged with a low torque capacity when an oil pressure is supplied to one of the hydraulic oil chambers and with a high torque capacity when an oil pressure is supplied to the two hydraulic oil chambers.